The present invention relates to imaging devices and, more particularly, to high-dynamic-range imaging systems.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an image sensor having an array of image pixels and a corresponding lens. Some electronic devices use arrays of image sensors and arrays of corresponding lenses.
In certain applications, it may be desirable to capture high-dynamic range images. While highlight and shadow detail may be lost using a conventional image sensor, highlight and shadow detail may be retained using image sensors with high-dynamic-range imaging capabilities.
Common high-dynamic-range (HDR) imaging systems use multiple images that are captured by the image sensor, each image having a different exposure time. Captured short-exposure images may retain highlight detail while captured long-exposure images may retain shadow detail. In a typical device, image pixel values from short-exposure images and long-exposure images are selected to create an HDR image.
When capturing images from highly dynamic scenes (i.e., scenes having a high dynamic range), conventional image systems may capture images using inappropriate exposure times for a given scene, which may cause insufficient dynamic range capture in a combined HDR image.
It would therefore be desirable to provide improved imaging systems and exposure methods for high-dynamic-range imaging.